Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductive layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon. Many integrated circuits are typically manufactured on a single semiconductor wafer, and individual dies on the wafer are singulated by sawing between the integrated circuits along a scribe line. The individual dies are typically packaged separately, in multi-chip modules, or in other types of packaging, for example.
A MOSFET with stressor regions is often formed by using epitaxially grown semiconductor materials to form source and drain features. Various techniques directed at the shapes, configurations, and materials of the source and drain features have been implemented to further improve transistor device performance.
Although existing approaches have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects.